Originally Posted by sikclown
The Sim Unlocked HTC One is compatible with all bands of AT&T (This and the Developers versions are basically unbranded AT&T phones) and most of T-Mobiles Bands. It does not have support for T-Mobile's HSPA+ 42 1700mhz but it does support their 1900 mhz HSPA+ 21 as well as their LTE Band 4 and 17(?). I will say this though, you are better off just buying T-Mobile's Version from T-Mobile as it is the only version that will support all of their bands. You can then get T-Mobile to unlock the SIM. Call telesales and tell them you want to buy the phone outright and see if that works. Or see if they will let you pay off the phone early? Regardless I think we have now officially beaten the proverbial dead horse.
Not to drift too far off topic but sim unlocks on T-Mobile and AT&T are damn near impossible to get right now.
I have a friend with the T-Mobile version bought outright and they will absolutely not give it to him citing x days in service, etc etc etc...
His battle is ongoing...
My battle with AT&T..... I was able to prevail in getting an unlock but it took
intervention and a near 3 week fight.
That's a whole other story...
Now... as far as anyone can tell there may be some subtle hardware differences between the T-Mobile and AT&T versions.
This does not appear to be a matter of simply swapping radio images as it was on some Samsung phones. (Note IIRC?)
If your going to get a phone and use it on T-Mobile.. and you don't care about HSPA on AWS or LTE then an unlocked one may be for you.
Otherwise.. best to stick to the carrier variant and get S-OFF via JTAG if you really want it... or just use htcdev.